The present disclosure relates to an imaging device, an image signal processing method, and an image signal processing program.
There is known a method for imaging an object under the condition that almost no visible light is available, such as during nighttime, by radiating infrared light onto the object from an infrared projector and imaging infrared light reflected by the object. This imaging method is effective in a case where lighting fixtures for radiating visible light cannot be used.
However, since an image obtained by imaging the object by this method is a monochromatic image, it is difficult to identify the object from the monochromatic image depending on circumstances. If a color image can be captured even under the condition that no visible light is available, the performance of identifying the object can be improved. For example, it is expected that surveillance cameras can capture color images under the condition that no visible light is available in order to improve performance for identifying objects.
Japanese Unexamined Patent Application Publication No. 2011-050049 (Patent Document 1) describes an imaging device capable of capturing color images under the condition that no visible light is available. The imaging device described in Patent Document 1 uses an infrared projector. Incorporating the technique described in Patent Document 1 into a surveillance camera can capture a color image of an object so as to improve the identification of the object.